Injection molding is a modern science used to mold liquid plastic resins into solid objects. It is a multi-billion dollar business that produces 32% of the world’s plastic. The machine has six basic parts, and the process involves pouring liquid resin into the hopper, heating it, and injecting it into the mold. The mold determines the shape of the finished product, and problems can be easily fixed.
Molding liquid plastic resins into solid, usable objects and parts is a modern science that is commonly done using an injection molding machine. Machines come in various sizes, with the size of the machine determined by the desired size of the finished product. Invented in 1872, the injection molding process revolutionized the plastics industry. It is currently a multi-billion dollar business that produces about 32% by weight of all the world’s plastic. Its popularity is attributed to the injection molding process and machines that make millions of consumer products and the production of affordable, yet durable and long-lasting parts and components.
The construction and operation of the injection molding machine is quite simple. The machine is made up of six basic parts. The main components of the machine include a hopper where the raw materials are fed, a barrel to transport the materials to the heating unit, a heater to break down the materials into liquid, a nozzle to pump the liquid into the mold, a clamping unit to solidify the shape, and an ejector to eject the finished product.
To produce an injection molded product, liquid resin is poured into the hopper of the injection molding machine, followed by colorants or tints. Gravity draws the resin into the barrel and the heating process melts the resin into a smooth liquid. An injection mechanism, usually a reciprocating screw or piston injector, forces the liquid into the mold. If small amounts of resin are desired in the mold, the alternate screw is used as it can only inject 5% of the full amount into the hopper. The piston injector is used when at least 20% of the total amount in the hopper needs to be forced into the mold.
The mold determines the shape for the finished product and cools the liquid into a solid. During cooling, the mold plates are held together by mechanical or hydraulic force. This clamping procedure determines the final shape of the finished product. Since different resins have different shrinkage rates, the molds are designed with specific resins in mind.
Problems with injection molding machine performance are usually simple and easily fixed. Burnt or scorched parts can be avoided by lowering the hopper temperature or reducing processing times. Warping is normally resolved by adjusting the surface temperature of the mold or adjusting the thickness of the mold. Imperfections on the product surface can be corrected by adjusting the mold temperature, humidity levels or pressure.
Protect your devices with Threat Protection by NordVPN
